CHICAGO (CBS) — If you’ve felt like you’ve been living in San Francisco the past couple weeks, that’s just another weird weather phenomenon you can blame on the brutal weather this past winter.

WBBM Newsradio’s Mike Krauser reports the fog is a result, in part, of the infamous “polar vortex” that brought frigid temperatures and heavy snowfall to the region.

“It is a vestige of that, and the unusually cold winter we had, and the cold water temperatures that were a result of that. Those water temperatures are slowly climbing,” said AccuWeather meteorologist John Gresiak.

The temperature of Lake Michigan has been in the mid- to upper-60s along the shore, but in the middle of the lake, the water is still in the 40s, and even the upper 30s in some spots.

Gresiak said the other factor has been all the moisture in the air lately.

“What we’re looking at is basically the dew point temperature. If the dew point temperature is above the water temperature, then odds are you’re going to get some fog and low clouds,” he said.

Other cities on the lake also have been experiencing foggy conditions in the past couple weeks.